Background and goals - Long-term opioid therapy for chronic non-cancer pain (CNCP) has increased dramatically in recent years, especially among middle aged and older adults. More than 8 million American adults now use opioids for long-term management of CNCP, but there are substantial individual differences in pain control and psychosocial outcomes among these patients. Differentiating patients likely to experience favorable outcomes from those who may have opioid-related difficulties and unfavorable psychosocial outcomes on chronic opioid therapy is now a problem of substantial clinical and public health significance. This research will clarify individual risks among patients initiating chronic opioid therapy, laying the foundation for early identification of patients at high risk of unfavorable psychological and functional outcomes. Among middle aged and older adults initiating long-term opioid use, this research will: 1) identify predictors of sustained opioid use; 2) evaluate risk factors for psychosocial dysfunction; and, 3) develop practical methods for early identification of patients at increased risk of unfavorable psychosocial outcomes. Methods - A Study Cohort will be formed with 1500 middle aged and older CNCP patients initiating long- term use of prescribed opioids. Data will be obtained through study participant interviews at baseline and at follow-ups 3 and 12 months later, and from health plan electronic medical records data. Using these data, the proposed research will address the following specific aims: Aim 1: Identify predictors of long-term opioid use - Baseline variables will be evaluated to identify predictors of continued opioid use at one year and to understand factors influencing sustained use. Aim 2: Identify risk factors for psychosocial dysfunction - Risk factors for psychosocial dysfunction at one year follow-up will be evaluated among patients initiating long-term opioid use. Aim 3: Develop clinical prediction models - Clinical prediction models for psychosocial dysfunction at one year will be developed from baseline data. Impact: This research will yield new insights into the development and prediction of unfavorable psychosocial outcomes among CNCP patients initiating chronic opioid therapy. This research will help practicing clinicians identify, early in an episode of opioid use, patients likely to sustain opioid use and those at high risk of unfavorable psychosocial outcomes. This will afford opportunities to reduce risks of unfavorable psychological and functional outcomes among these patients. 1